1. Field of the Invention
The present invention relates to a head cleaning device for cleaning a magnetic head for use in a magnetic recording and reproducing apparatus and, more particularly, to a head cleaning device for removing deposits adhering to such magnetic head therefrom.
2. Description of the Prior Art
Reproducing with high reliability the signal recorded to magnetic tape is an essential requirement for any magnetic recording and reproducing apparatus. After extended operation, however, magnetic particles, binder, resin, and other constituents of the magnetic tape separate from the tape and adhere to the head surface in contact with the magnetic tape. This results in a variety of problems relating to the electromagnetic conversion characteristics of the magnetic head, particularly reduced output, clogging, and signal dropout.
Various methods of removing these deposits from the sliding contact surface of the magnetic head have been proposed in, for example, U.S. Pat. No. 4,462,056 which was issued to Kara Jul. 24, 1984 and U.S. Pat. No. 5,012,376 which was issued to Joannou et al. These methods make it possible to remove deposits with a relatively weak force acting on the magnetic head surface. Under low humidity conditions, however, seized deposits with a bonding strength greater than the relatively weak force applied by the above methods are also formed from the magnetic tape onto the sliding surface of the magnetic head, resulting in the occurrence of so-called brown strain on the magnetic head surface. As a result, the operating range of these methods is limited.
The brown stain cited in this invention is described briefly below. Moisture in the air is absorbed by the surfaces of the various components associated with the relative movement of the magnetic tape to the magnetic head, which rotates at high speed, and contributes to the smooth movement of the tape relative to the magnetic head by acting as a lubricating film. In low humidity conditions, however, the contribution of ambient moisture to this smooth movement is reduced, increasing the coefficient of friction between the tape and head, and increasing the degree of direct contact between the tape and head.
Particulate separating from the magnetic layer of the tape then triggers the production of seized deposits with a high adhesive strength on the sliding surface of the magnetic head. These seized deposits cannot be removed by a simple solvent and wiping action, and therefore gradually accumulate, creating a spacing loss between the magnetic head and magnetic tape that results in reduced output characteristics.